Preparation for washing living hair



Patentedluly 7, 1942 UNITED STATES. PATENT OFFICE 2,289,004 BREPARATIONFOR WASHING LIVING HAIR. Ehrhart Franz, Leipzig, Germany No Drawing.Application April 29, 1937,

- Serial No. 139,715

1 Claim. (Cl. 252-161) This invention relates to a process for washingliving hair and to agents adapted to carry out this process.

It is a continuation in part of applicant's United States patentapplication, Serial No. 656,594 of February 13, 1933, on Process ofwashing living hair. 1

It is an object of this invention to provide an agent, which effectivelycleanses living hair; but the agents shall not injure the hair; i. e.they shall not cause loss of vitality; nor render the hair undulysensitive nor change its normal behavior in respect to light, weather orexudations of the body; nor shall such agents unfavorably affect thephysical behavior'and properties, or the chemical composition of thehair.

The invention concerns treatment of the living hair with washing agentscomprising organic compounds of hexavalent sulphur of the generalformula RrSOaMe, in which:

R represents 'an organic radical of the ali-' phatic series,particularly a straight aliphatic chain having more than carbon atoms; Rmay be substituted, e. g. by a nitrogenous radical; and it may comprisefor connection with the SO3- radical an oxygen atom or certain organicgroups.

Me stands for a metal of the alkalies or a nitrogenous radical that issaliflable.

Compounds of this class have been applied be fore for washing textiles,but only together with soap which is added to a solution of such adetergent or formed in the textile material from the oleic acid or asalt thereof due to greasing. However, a neutral or acid washing processwith the compounds in questiln has never been adopted by the textileindustry; the usefulness of these compounds was thus restricted to a fewlimited, special applications, in connection with which their defectsand costs were favorably offset by certain advantages; and for thatreason they were used in preference to other agents.

My experiments have revealed, however, that the compounds referred toexcel at a surprising degree in the treatment of living air in thepresence of certain substances which possess protecting and conservingcharacteristics, and their use in this respect constitutes aconsiderable advance in the art.

It is well known that animal and especially human hair is seriouslyinjured when treated with the usual washing agents. Such substances,which rely on an alkaline action, attack the protein molecules of thehair, the micellar structure is loosened, and

luster, becomes brittle, hard and inelastic, and at times even changesin color. The harm which is thus caused cannot be counteracted andovercome by the most thorough rinsing, nor by after-treatments withacids, which are to remove the adsorbed alkali.

Hair consists of very complex protein molecules which are arranged likethreads to form micellae. The diversity and complex arrangement of theelements aggregating such molecules involves great exposure to attack,and in the protein molecule numerous chemical reactions find anopportunity to set in. The inner structure of the molecule, i. e. thegrouping of basic and acid radicals, insures interior neutralization ofthe intramolecular kind, and only the sum of such intramolecularneutralizations 'afiects the outer character of the molecule and thus ofthe hair.

Normal hair has an isoelectric point corresponding to a pH value of 4.6,so that the compound is comparatively strongly acid. Aqueous washingsolutions having such a pH value exert .no influence upon the hairbecause it remains neutral and indifferent to them. But solutions oflower and higher pH values are capable of reacting upon the hair, forexample they cause a swelling of the hair. Such swelling, however, isharmful and a start of further and. greater damage.

On the other hand, all the ordinary washing agents show a greaterwashing power at a higher pH value; but if aqueous solutions of suchhigher pH value are used in treating hair, particularly human livinghair, extraordinary injury will be inflicted, even though the hair maybe exposed to their action for only a very short period of time. Underthese conditions such washing agents should have a pH value of less than'7. If we use, for instance, soap at a pH value of '7, and thus face thefact that a certain amount of the damage will be done to the hair, thecleansing efiect is not only practically nil, but in addition, the hairwill be soiled by fatty acid which has separated. Therefore soap andproducts containing soap are not suited all for acid washing livinghair.

The use of soap involves additional disadvantages: Frequent washingofliving hair irritates the capillary matrix and causes excessivesecretion on the part of the sebaceous glands. This is due not only toexcessive degreasing of the capillary matrix and the hair, but allsolutions which react alkaline lead to similar phenomena. Such the hairloses its abnormal activity of the sebaceous glands expedites thegreasing of the hair which proceeds from the root in the direction ofthe tips of the hair; there is new cause for soiling of the hair, sothat the hair will have to be washed again after a short time and thenew irritation stimulates the sebaceous glands still more. It finallybecomes necessary to wash the hair every other or third day. It has beenattempted to overcome this drawback by adding astringents, such as weaktanning agents like tannin, acids, etc.; but without much success,because the astringent effect of such agents is known to be quite low inthe higher pH range, and the washing action of soap is limited to pHvalues over 7.

The marked degreasing effect of the new washing agents of thisinvention, which is still greater than that of soap, raised thepresumption that in their use on hair the above-mentioned drawback wouldbecome still more pronounced than in case of soap. It is surprising,that the opposite could be proved: The irritation of the sebaceousglands is greatly reduced. This is due to the constitution of the newwashing agents, which insures an astringent effect by virtue of theneutral acid state of the aqueous solutions.

The washing agents of this invention can be used in the range of pHvalues below 8 so that they act as tanning substances. That effect canbe intensified by suitable additions of acids and the like to the extentof excluding any excessive secretion of fat. A shortage in the secretionof fat can be offset by the addition of fatty substances to the washingagent or by greasing the hair during or after washing.

Comparative tests with modern washing agents employed in washing wooland other dead hair do not shown any superiority over soap, except thatthe washing time is sometimes shortened a little and the washingmaterial is opened more. Inventors experiments, which have beenconfirmed by many other authors, show that neither the elasticproperties nor the ductility, length and thickness of the hair aredifierently influenced by one or the other of the groups of washingagents. It was therefore quite surprising to find out that conditionsare totally different in respect to living, and more particularly tohuman hair.

Washing agents for living hair, such as shampoos, act not only on thehair that has come out of the root, but also on the root itself, atleast upon the upper part thereof, as well as on the papilla and thecapillary matrix. In so far as the customary washing agents containalkali or lipoid-soluble substances, such as organic solvents orlipoid-solubleby-products, there is always danger that not only thehair, but also the growth of the hair, i. e. the root and the capillarymatrix, will be injuriously affected.

Their excellent cleansing action notwithstanding, all organic solventsmust therefore be eliminated. It cannot even be predicted whether thewater-soluble solvents, as polar compounds, still possess too muchsolubility in lipoid and thus might injure the centers of growth of thehair.

Organic solvents are capable of separating the intra-capillary andintramicellar fat from the hair; they replace this fat to a large extentin the intermediate spaces where they are diflicult to remove, so thatit is not possible duly to supply fat to the spaces occupied by them. Ithas been found out long ago that too much degreasing means enormousdamage to the hair. Such degreasing is not possible, when we wash in anacid medium.

Furthermore, when washing with the new washing agents of this invention,especially in a medium of lower pH value, a fat or a fatting agent maybe added to the washing agent 01' the washing mixture. During such awashing, the new washing agents, as complex molecular substances, areunable to enter the interior of the hair. The surface only is degreased,and by adding fat to the washing agent undesirable degreasing isavoided.

For washing a highly sensitive material like living hair, specialpreparations of the agents in question should be used, from whichinorganic and organic impurities have been substantially removed. Withsuch preparations it is possible to wash at pH values which approachvery closely the iso-electric point pH=4.5 of the hair, especially at pHvalues at which washing with soap is out of question.

Soap causes further injuries. Hard water, i. e. water containing lime,magnesium salts or others, leads to the formation of sebacic fatty acidsalts insoluble in water while the lime liberates alkaline hydroxide;the precipitated salts embed in the surface capillaries and cracks andare capable, by pressure of crystallization of loosening the hair. Theembedded salts also promote trituration of the hair, due to mechanicalstressing. The magnesium and lime soaps, which are produced, also havethe disadvantage of being filtered off in the hair, of reducing itsluster and of decreasing the speed of drying.

In the treatment of living hair with mixtures of this invention the hairretains its chemical composition and its physical and biologicalproperties and is merely freed of dirt and excess fat. The applicabilityof the washing agents of this invention under the conditions and for thepurpose stated could not be foreseen and had to be ascertained bymethodic and exact experiments. All agents found to be suitable have thecommon feature that they contain more than 11 carbon atoms preferablyarranged in an aliphatic chain.

From the point of view of physical chemists the compounds representpolar compounds, i. e., they possess a group insuring solubility inwater and a complex pyridine-like rest. There are first the sulphuricesters or their salts.which can be produced from acids like lauric,myristic, palmitic, stearic and oleic acid, by means of a reduction ofsaid acids to the corresponding alcohols, or directly from the alcohols.Compounds containing an uninterrupted chain 12, 14, l6, 18 of carbonatoms in the molecule are suited. Compounds with less than 11 carbonatoms are no Washing agents proper, though they may be useful as foamingadditions. Compounds with 11, 13. 15, 17 and 19 carbon atoms do not comeinto question because they are not commercially available. In otherconfigurations compounds with more carbon atoms may be considered, butin the straight line chain only the first mentioned compounds with 12,14, 16 or 18 carbon atoms come into question, e. g.butylmethylcyclohexanol sulphuric acid; octadecenoylmethylaminoethanolsulphuric acid or its sodium salt; hexadecoyloxyethanol sulphuric acidor its ammonium salt, dichlor-octadecoylaminopropanol sulphuric acid orsalts thereof, chloroctadecanol sulphonic acid salts, similar halogensalts, etc.

Such compounds, so-called sulphuric acids or sulphates, should be intheir. pure state; in particular lipoid-soluble by-products, such as thedi-alky1-sulphates, must be eliminated. Furthermore. inorganicby-products developed during production, especially sodium sulphate,should be removed from the preparation to a predetermined extent. Thepresence of such salts must be carefully limited, since any loading ofthe living hair with such inorganic products is undesirable; theyrepresent or lead to injury.

Particularly useful are the above mentioned sulpho acids, or saltsthereof, corresponding for example, to the sulphuric esters mentioned,as they can easily be obtained from these esters with the acid of sodiumsulphite, though the sulpho salts are somewhat less soluble than thecorresponding ester salts. However, such sulpho acids, unlike any of theesters, cannot decompose under the action of catalysers and enzymes bydividing into the alcohol and the sulphuric acid. That would causeconsiderable injury and irritation to the living hair. Therefore thesaid sulpho acids as well as their salts are generally to be preferred.But that does not preclude esters, which have been carefully prepared toprevent decomposition, or which are protected against decomposition bysuitable additions, as known.

It is further possible to employ compounds which carry in the aliphaticrest a carboxyl group which should be closed by esterificationpreferably with the aid of butyl alcohol.

. Among the suitable sulpho acids and their salts those are particularlyuseful which contain, besides the sulpho group, a hydroxyl-like radicalwhich has a slight polar effect. As such radicals serve, above all, thecarbonamides and sulphamides. Examples of compounds with sulpho groupsand acid amide groups with an uninterrupted aliphatic chain with astraight series of more than 11 carbon atoms are oleic acid-amide-sulphoacid, oleoylamidethane-sulpho-acid, oleoylmethylamidoethane-sulpho acid,dodecoylamino-propanesulpho-acid, tetradecylsulphamidoethanesulpho acid,methionic acidmonocethylamide, and the corresponding carbonarnide of thesulphopropionic acid (sulphopropionylethylamide). An equally usefulcompound containing an aromatic residue is oleoylaminosalicylsulphoacid, in which between the sulpho group and the aliphatic chain thesalicyl radical has replaced the ethylene radical.

Excellently suited are further the aliphatic thiosulphates, compoundswhich may be regarded as sulphuric esters of aliphatic thioalcohols orsalts thereof. They can be readily obtained by conversion of the abovementioned sulphuric esters with sodium thiosulphate, or from thecorresponding alkyl halides by conversion with sodium thiosulphate. Suchcompounds are much more stable than the corresponding alcohol sulphuricesters. Special mention of this series deserves sodiumdodecyl-thiosulphate, sodium hexadecanthiosulphate. The last-mentionedcompounds are effective for preventing scale, and this effect may beimparted to the washing agents also by the addition of compounds likeresorcin ether, cystin and the like.

All the compounds mentioned can be applied in the form of their salts,of which the alkali and ammonium salt are especially useful, though thesalts of other organic bases, like the salt of triethanolamine orethanolarnine or aminoglycerine, can be employed also.

When the acids are used, or, generally, for the purpose of preventingtoo low a pH value, the addition of buffer substances, such as sodiumbicarbonate, phosphates (ortho-, pyroand metaphosphates) borates,tern-ates, citrates and the like, may be advisable. By use of the saltthe buffer agent may become a weak acid or an acid salt. The use ofwashing acids (W-SOaH) together with bufiering salt is the same as theuse of washing salt together with buffering i. e. weak acids W--SO:H +Naboratez WSOaNa+boric acid.

Together with ester salts it is preferable to add a salt of a weak acidfor neutralizing, i. e. as a buffer against whatever sulphuric acid oracid sulphates may be generated.

Together with said washing agents or washing agents and buffers we mayuse compounds which diminish or make possible an attack upon thematerial; they suit such purpose if they either increase the washingeffect, or have protective characteristics of the order found in theabove- As preserving agents protein compounds are v particularlysuitable, or protein decomposition products like sodium lysalbinate orprotalbinate or sebacinate. Compounds like these are useful because theydisplace the isoelectric point of the hair in the direction of higherpH-values; they also act as buffers, because they counteract thedestructive effect of larger amounts of alkali. For the same purposeaibuminous products like gelatin and glue may be used. Otherwatersoluble compounds yielding solutions which are to a large extentcolloidal, such as sugar and sugar-like products, have a similar effect.

Examples (l) Angora rabbit hair is dusted with sodium dodecyl-sulphate,containing 1% tartaric or citric acid. By the use of lukewarm water, thepreparation is caused to foam in the hair until foaming ses. The wash isallowed to act for some tim-, and then it is rinsed in lukewarm water.The hair will be found to be perfectly clean; it has been sufficientlybut only superficially degreased; and it is loose and soft.

(2) Living animal hair is treated with a solution containing 2% ofhexadecylsulphonic acid and 1% of sodium borate or borax at about 30 to35 C. After treatment the hair is thoroughly rinsed, and dried as usual.As necessary, fat may be introduced into the hair.

(3) Human hair is treated with a 1% solution of sodiumoleoylmethylaminoethanesulphonate at 40 to 50 0., containing preferablya weak acid or an acid salt, such as sodium bicarbonate or bitartrate. Aheavy foam is produced, and is allowed to remain 3 to 5 minutes inintimate contact with the hair. Then the hair is thoroughly rinsed withlukewarm water. It is advisable to add to the hair during or afterwashing a certain amount of fatty substance, especially when the hair ispoor in fats. Instead of the sodium salt an organic salt of the sulphoacid may be used, such as the triethanolaminates of such an acid.

Preparations for treating living hair should be used in as pure a stateas possible; such state can be effectively and simply attained asfollows:

The commercial preparation is boiled with 6 to 10 times the amount ofethyl alcohol, so that the organic salt passes into solution, allinorganic impurities forming the residue. In order to economize insolvents, the preparation may be extracted by means of a suitableextracting device; when the alcohol cools off, the organic salt willusually divide out. After evaporation of the alcohol, the product isdried and then treated with benzine, benzene or the like in order toremove water-insoluble impurities. One of the greasing agents mentionedabove, e. g. wool grease, and/or a buffer such as weak acid or an acidsalt of such Weak acid to the or a salt of weak acid to the washing acidmay be added, and the washing process cannot possibly harm the hair.Even if this reduces the washing power to a slight extent, it alsoprevents excessive removal of fats from the surface of the hair.

(4) 40 parts by weight of sodium dodecanol ,sulphate (freed of organicimpurities by dissolving in alcohol), or like parts of ammoniumtetradodecyl alcohol sulphuric sulphate are dissolved in 100 parts ofwater. While stirringwell approximately 4 parts by weight of thehydrophile portion of wool fat (lanolin) are added, and so much citricacid, as necessary to start litmus paper to turn red. By suitableaddition the resultant colloidal solution may be colored and/or scented,as circumstances may require. The product is an excellent solution forwashing hair, and is particularly useful for hair lacking fat. Whenhydrogen-peroxide is admixed to the hair washing salts,

with the resultant hair-washing powder, moistened and worked until afoam of fine structure is formed, which is allowed to remain in contactwith the hair for a short period of time. For a rinse a 0.1% solution ofsodium dodecyl sulphate is advisable to use. An emulsion of lanolin in asolution of sodium dodecyl sulphate or sodium hexadecyl sulphate,hexadecyl alcohol may be added. may be applied to and worked into thehair, before it is finally rinsed with clear water.

(7) 30 parts by weight of purified sodium tetradecanol sulphonate, whichhas been well dried and comminuted or which has been reduced to a finepowder by simultaneously atomizing and drying a watery solution thereof,are mixed with parts by weight of soluble, completely dry starch. 15parts of well dried di-sodium phosphate and 20 parts of sodiumbicarbonate are added.

This hair washing preparation yields a very fine, dense foam, theformation of foam being enhanced by the effervescence of carbon dioxide.

, moistened state.

washing solution, we obtain an excellent hairwash for combined bleachingand washing effects.

(5) Like the sodium dodecanol sulphate we may also purifytriethanolamine, or sodium octadecenoylmethylaminoethanesulphonate, orsodium octadecenoyloxyethane sulphonate by dissolving in alcohol and byextraction of a watery solution with petroleum ether or benzene. Thesulphate or anyone of the other compounds so purified is reduced withwater to a paste, using substantially the aforementioned proportions.

Instead of the salt we may use the corresponding acid in whole or inpart, adding as a buffer the salt of a weak acid, say 10 parts of sodiumtartrate.

Into such a paste we work burdock oil, until a saturation point has beenreached, such a point being indicated in a diluted sample by theformation of oily drops. Into the resultant paste we may introduce aperfume, as customary. This kind f a preparation is particularly suitedfor giving a second wash to hair, from which too much fat had beenremoved when it was washed the. first time. But the fatty contents ofthe preparation may also be adjusted in order to render it suitable fora general hairwash, by reducing or increasing the fatty contents in thecase of normal hair or of hair which is short in fat, respectively.

(6) 100 parts by weight of sodium dodecyl sulphonate, which may havebeen purified as suggested above, are mixed with 30 parts in weight ofsodium octylsulphate, and they are pulverized in a suitable container.They are mixed together with 10 parts in weight of finely groundcommercial sodium bicitrate or with 5 parts in weight of citric acidpowder.

Very fine powder of bran of wheat may also include some colloidal clay.The hair is dusted The above-mentioned purified washing agent may beothers, e. g. ammonium dodecanol sulphate or sodium dodecanol sulphate.Such a washing powder is preferably sprinkled in a dry state unto thehair which is in a dry or slightly The powder may be scented, if sodesired.

parts by weight of acid sodium pyrophosphate, and may then be suitablyscented. This preparation has characteristics similar to those ofExample 7.

The washing agent may be replaced by others, or we may use a mixture ofseveral washing agents. For such substitution 'or mixture we may alsouse the sodium salt of the sulphuric acid ester of cocoanut oil. Notparticularly useful by itself, but excellent in mixture is the sodiumsalt of the sulphuric acid esters of blubber (hexadecanol palmitate).

Not all similar compounds having corresponding constitutions can beused, but only those that, in aqueous solutions, show a certaincolloidal condition externally indicated by foaming. Some of thesecompounds are capable of foaming at low temperature, e. g., 18 C., butat higher temperature they will pass into genuine solutions and losetheir foaming capacity. Only acids and salts which are capable offoaming at both 18 and 50 C. can be used. This foaming and washing poweris not exclusively dependent upon the acid, i. e., the anion, but alsoupon the cation. Sodium salt for instance sometimes foams in colloidalsolution, whereas the more easily soluble potassium or ammonium saltwill be in genuine solution and not foam any more. Only the sodium saltwill then be useful, though,

because it tends to precipitate from the solution at low temperature, sothat only solutions of higher temperature can be used. Foaming ca pacitycan be ascertained in a very simple manner. All that is necessary is tofill a 1%-2% solution of the washing agents into a half-filled cylinderat the temperatures stated, shake it for 30 seconds and allow it tostand. The foam should keep for at least 2 to 3 minutes.

All preparations of this invention react acid upon phenolphthalein. Suchwashing agents an alkyl radical having an aliphatic series upward from11 carbon atoms, connected to the $02 by way of a link taken from thegroup consisting of O, S, CONH--R'-, -C0-NR."-R'-, -'C0-OR'- and O- R'-,wherein R stands for an alkylene radical and R" for methyl or ethyl, incombination with a weakly acid ingredient of a quantity sufficient torender the whole preparation acid in reaction.

EHRHART FRANZ.

